1. Field of the Invention
The present invention relates to a method for the preparation of a substance capable of proliferating the growth of bacteria belonging to the genus Bifidobacterium, i.e., bifidobacteria.
More particularly, the present invention relates to a method for the purification of a bifidobacteria-proliferating substance which is extracted from soybeans.
2. Description of the Prior Art
In general, bifidobacteria are recognized to have a physiological importance for humans. It is considered that bifidobacteria would be particularly effective for protection from intestinal infections, enhancement of immune function, prevention of enteric putrefaction, decomposition of carcinogenic substances, production of vitamins, etc.
In recent years, it has been attempted in the clinical field to orally administer bifidobacteria per se and this is based on the reports that bifidobacteria are effective for treatment of gastrointestinal disorders, hepatic disorders, skin diseases, allergic diseases, diseases caused by microbisme selectionne et substitue, etc. of babies, infants, adults and aged people.
Also for purposes of utilizing the effectiveness of bifidobacteria, bifidobacteria-containing foodstuffs such as cultured milk products, tableted candy, etc. are commercially available.
It is recognized also from a medical viewpoint that formation of bifidobacteria dominant flora in the intestinal tract of not only infants but also adults and senile people would be effective for prophylaxis of diseases and quick recovery from diseases. For this reason, it is desirable to always maintain a high population of bifidobacteria in the intestine.
If it is wished to temporarily increase bifidobacteria, it may be sufficient to consecutively administer bifidobacteria orally. As compared with the count of the living bifidobacteria orally administered, the count of the living bifidobacteria which can reach the intestinal tract is considerably fewer, because bifidobacteria have a low resistance to acids such as gastric acid, bile acid, etc. It is thus difficult to maintain the count of intestinal bifidobacteria on a high level merely by oral administration of bifidobacteria.
It is thus improtant to provide an environment for retaining and proliferating bifidobacteria in the intestine. For this reason, it has been attempted to maintain the count of intestinal bifidobacteria on a high level, by orally administering a bifidobacteria-proliferating substance either alone or in combination with bifidobacteria.
It is known in Japanese Patent Application Laid-Open Nos. 51-142566, 55-85390, etc. that soybean milk is effective for growth of bifidobacteria. However, it is quite unknown what component of soybean milk is effective.
Oligosaccharides such as stachyose, raffinose, etc. which are contained in soybeans are known as sugars capable of proliferating bifidobacteria.
However, even in the case of using these sugars, the effect of proliferating bifidobacteria is still inferior to that of a bifidobacteria-proliferating substance contained in soybean milk.